鄂西—渝东飞仙关组层序地层与滩体展布研究——以建南及周缘地区飞仙关组三段为例

Sequence stratigraphy and reef beach distribution of Feixianguan Formation in western Hubei-eastern Chongqing area: a case study of the third member of Feixianguan Formation in Jiannan and adjacent area

吴娜珠

WU Nazhu

中国石化 江汉油田分公司 物探研究院, 武汉 433100

Geophysical Research Institute of Jianghan Oilfield Branch Company, SINOPEC, Wuhan, Hubei 433100, China

应用钻井、录井、岩心、露头剖面、地震和分析测试等资料，对鄂西-渝东地区建南及周缘下三叠统飞仙关组三段生物礁滩体进行了层序界面识别、层序单元划分、等时地层格架建立和沉积体系分析。建南地区飞仙关组由SQ1和SQ2两个三级层序构成，其中SQ1由飞一段和飞二段构成，SQ2由飞三段和飞四段构成。飞三段又可进一步细分为3个四级层序，自下而上分别为sq1、sq2及sq3。飞仙关组三段沉积相可分为内缓坡、中缓坡和外缓坡相，进一步划分为鲕粒滩、暴露鲕粒滩、豆粒滩、生屑滩、砂屑滩、滩间、下斜坡、上斜坡及台洼等9个亚相。飞仙关组三段沉积期，研究区地势西高东低，高能的浅滩分布于中部地区，暴露鲕粒滩主要分布于研究区北部和南部，为主要的储集层。

The sequence boundary identification, sequence unit division, isochronous stratigraphic framework establishment and sedimentary system of bioreef-beach bodies in the third member of the Lower Triassic Feixianguan Formation in and around Jiannan town in the western Hubei and eastern Chongqing area were studied based on drilling, logging, core, outcrop, seismic and testing data. The Feixianguan Formation consists of two third-order sequences, SQ1 and SQ2. The SQ1 was composed of the first and second members of Feixianguan Formation, while the SQ2 was made up of the third and fourth members of Feixianguan Formation. The third member of Feixianguan Formation can be further refined into three fourth-order sequences, which are sq1, sq2, and sq3 from bottom to top. The third member of Feixianguan Formation can be divided into inner, central and outer gentle slope facies, and further divided into 9 beach subfacies, including oolitic, granulated, bean, biodetritus, sandy clastic and inter beaches, and lower slope, upper slope and platform depression. During the deposition of the third member of Feixianguan Formation, the terrain of the study area was high in the west and low in the east. The high-energy shoal was distributed in the central area,while the granulated beach and main reservoirs were mainly distributed in the north and south of the study area.

中国石化江汉油田分公司项目"鄂西渝东区二、三叠系礁滩精细刻画技术研究"资助。

https://doi.org/10.11781/sysydz201904524